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<a name="1" href="#1">1</a>   <em class="jxr_javadoccomment">/**</em>
<a name="2" href="#2">2</a>   <em class="jxr_javadoccomment"> * This is the 3rd version of org.graphnav.swing.SwingWorker (also known as</em>
<a name="3" href="#3">3</a>   <em class="jxr_javadoccomment"> * org.graphnav.swing.SwingWorker 3), an abstract class that you subclass to</em>
<a name="4" href="#4">4</a>   <em class="jxr_javadoccomment"> * perform GUI-related work in a dedicated thread.  For</em>
<a name="5" href="#5">5</a>   <em class="jxr_javadoccomment"> * instructions on using this class, see:</em>
<a name="6" href="#6">6</a>   <em class="jxr_javadoccomment"> *</em>
<a name="7" href="#7">7</a>   <em class="jxr_javadoccomment"> * <a href="http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html" target="alexandria_uri">http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html</a></em>
<a name="8" href="#8">8</a>   <em class="jxr_javadoccomment"> *</em>
<a name="9" href="#9">9</a>   <em class="jxr_javadoccomment"> * Note that the API changed slightly in the 3rd version:</em>
<a name="10" href="#10">10</a>  <em class="jxr_javadoccomment"> * You must now invoke start() on the org.graphnav.swing.SwingWorker after</em>
<a name="11" href="#11">11</a>  <em class="jxr_javadoccomment"> * creating it.</em>
<a name="12" href="#12">12</a>  <em class="jxr_javadoccomment"> */</em>
<a name="13" href="#13">13</a>  
<a name="14" href="#14">14</a>  <strong class="jxr_keyword">package</strong> org.graphnav.swing;
<a name="15" href="#15">15</a>  
<a name="16" href="#16">16</a>  <strong class="jxr_keyword">import</strong> javax.swing.SwingUtilities;
<a name="17" href="#17">17</a>  
<a name="18" href="#18">18</a>  
<a name="19" href="#19">19</a>  <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> <strong class="jxr_keyword">class</strong> <a href="../../../org/graphnav/swing/SwingWorker.html">SwingWorker</a> {
<a name="20" href="#20">20</a>  
<a name="21" href="#21">21</a>      <strong class="jxr_keyword">private</strong> Object value;
<a name="22" href="#22">22</a>  
<a name="23" href="#23">23</a>      <em class="jxr_javadoccomment">/**</em>
<a name="24" href="#24">24</a>  <em class="jxr_javadoccomment">     * Class to maintain reference to current worker thread</em>
<a name="25" href="#25">25</a>  <em class="jxr_javadoccomment">     * under separate synchronization control.</em>
<a name="26" href="#26">26</a>  <em class="jxr_javadoccomment">     */</em>
<a name="27" href="#27">27</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">class</strong> <a href="../../../org/graphnav/swing/SwingWorker.html">ThreadVar</a> {
<a name="28" href="#28">28</a>          <strong class="jxr_keyword">private</strong> Thread thread;
<a name="29" href="#29">29</a>          <a href="../../../org/graphnav/swing/SwingWorker.html">ThreadVar</a>(Thread t) { thread = t; }
<a name="30" href="#30">30</a>          <strong class="jxr_keyword">synchronized</strong> Thread get() { <strong class="jxr_keyword">return</strong> thread; }
<a name="31" href="#31">31</a>          <strong class="jxr_keyword">synchronized</strong> <strong class="jxr_keyword">void</strong> clear() { thread = <strong class="jxr_keyword">null</strong>; }
<a name="32" href="#32">32</a>      }
<a name="33" href="#33">33</a>  
<a name="34" href="#34">34</a>      <strong class="jxr_keyword">private</strong> <a href="../../../org/graphnav/swing/SwingWorker.html">ThreadVar</a> threadVar;
<a name="35" href="#35">35</a>  
<a name="36" href="#36">36</a>      <em class="jxr_javadoccomment">/**</em>
<a name="37" href="#37">37</a>  <em class="jxr_javadoccomment">     * Get the value produced by the worker thread, or null if it</em>
<a name="38" href="#38">38</a>  <em class="jxr_javadoccomment">     * hasn't been constructed yet.</em>
<a name="39" href="#39">39</a>  <em class="jxr_javadoccomment">     */</em>
<a name="40" href="#40">40</a>      <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">synchronized</strong> Object getValue() {
<a name="41" href="#41">41</a>          <strong class="jxr_keyword">return</strong> value;
<a name="42" href="#42">42</a>      }
<a name="43" href="#43">43</a>  
<a name="44" href="#44">44</a>      <em class="jxr_javadoccomment">/**</em>
<a name="45" href="#45">45</a>  <em class="jxr_javadoccomment">     * Set the value produced by worker thread</em>
<a name="46" href="#46">46</a>  <em class="jxr_javadoccomment">     */</em>
<a name="47" href="#47">47</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">synchronized</strong> <strong class="jxr_keyword">void</strong> setValue(Object x) {
<a name="48" href="#48">48</a>          value = x;
<a name="49" href="#49">49</a>      }
<a name="50" href="#50">50</a>  
<a name="51" href="#51">51</a>      <em class="jxr_javadoccomment">/**</em>
<a name="52" href="#52">52</a>  <em class="jxr_javadoccomment">     * Compute the value to be returned by the &lt;code&gt;get&lt;/code&gt; method.</em>
<a name="53" href="#53">53</a>  <em class="jxr_javadoccomment">     */</em>
<a name="54" href="#54">54</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> Object construct();
<a name="55" href="#55">55</a>  
<a name="56" href="#56">56</a>      <em class="jxr_javadoccomment">/**</em>
<a name="57" href="#57">57</a>  <em class="jxr_javadoccomment">     * Called on the event dispatching thread (not on the worker thread)</em>
<a name="58" href="#58">58</a>  <em class="jxr_javadoccomment">     * after the &lt;code&gt;construct&lt;/code&gt; method has returned.</em>
<a name="59" href="#59">59</a>  <em class="jxr_javadoccomment">     */</em>
<a name="60" href="#60">60</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> finished() {
<a name="61" href="#61">61</a>      }
<a name="62" href="#62">62</a>  
<a name="63" href="#63">63</a>      <em class="jxr_javadoccomment">/**</em>
<a name="64" href="#64">64</a>  <em class="jxr_javadoccomment">     * A new method that interrupts the worker thread.  Call this method</em>
<a name="65" href="#65">65</a>  <em class="jxr_javadoccomment">     * to force the worker to stop what it's doing.</em>
<a name="66" href="#66">66</a>  <em class="jxr_javadoccomment">     */</em>
<a name="67" href="#67">67</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> interrupt() {
<a name="68" href="#68">68</a>          Thread t = threadVar.get();
<a name="69" href="#69">69</a>          <strong class="jxr_keyword">if</strong> (t != <strong class="jxr_keyword">null</strong>) {
<a name="70" href="#70">70</a>              t.interrupt();
<a name="71" href="#71">71</a>          }
<a name="72" href="#72">72</a>          threadVar.clear();
<a name="73" href="#73">73</a>      }
<a name="74" href="#74">74</a>  
<a name="75" href="#75">75</a>      <em class="jxr_javadoccomment">/**</em>
<a name="76" href="#76">76</a>  <em class="jxr_javadoccomment">     * Return the value created by the &lt;code&gt;construct&lt;/code&gt; method.</em>
<a name="77" href="#77">77</a>  <em class="jxr_javadoccomment">     * Returns null if either the constructing thread or the current</em>
<a name="78" href="#78">78</a>  <em class="jxr_javadoccomment">     * thread was interrupted before a value was produced.</em>
<a name="79" href="#79">79</a>  <em class="jxr_javadoccomment">     *</em>
<a name="80" href="#80">80</a>  <em class="jxr_javadoccomment">     * @return the value created by the &lt;code&gt;construct&lt;/code&gt; method</em>
<a name="81" href="#81">81</a>  <em class="jxr_javadoccomment">     */</em>
<a name="82" href="#82">82</a>      <strong class="jxr_keyword">public</strong> Object get() {
<a name="83" href="#83">83</a>          <strong class="jxr_keyword">while</strong> (<strong class="jxr_keyword">true</strong>) {
<a name="84" href="#84">84</a>              Thread t = threadVar.get();
<a name="85" href="#85">85</a>              <strong class="jxr_keyword">if</strong> (t == <strong class="jxr_keyword">null</strong>) {
<a name="86" href="#86">86</a>                  <strong class="jxr_keyword">return</strong> getValue();
<a name="87" href="#87">87</a>              }
<a name="88" href="#88">88</a>              <strong class="jxr_keyword">try</strong> {
<a name="89" href="#89">89</a>                  t.join();
<a name="90" href="#90">90</a>              }
<a name="91" href="#91">91</a>              <strong class="jxr_keyword">catch</strong> (InterruptedException e) {
<a name="92" href="#92">92</a>                  Thread.currentThread().interrupt(); <em class="jxr_comment">// propagate</em>
<a name="93" href="#93">93</a>                  <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">null</strong>;
<a name="94" href="#94">94</a>              }
<a name="95" href="#95">95</a>          }
<a name="96" href="#96">96</a>      }
<a name="97" href="#97">97</a>  
<a name="98" href="#98">98</a>  
<a name="99" href="#99">99</a>      <em class="jxr_javadoccomment">/**</em>
<a name="100" href="#100">100</a> <em class="jxr_javadoccomment">     * Start a thread that will call the &lt;code&gt;construct&lt;/code&gt; method</em>
<a name="101" href="#101">101</a> <em class="jxr_javadoccomment">     * and then exit.</em>
<a name="102" href="#102">102</a> <em class="jxr_javadoccomment">     */</em>
<a name="103" href="#103">103</a>     <strong class="jxr_keyword">public</strong> <a href="../../../org/graphnav/swing/SwingWorker.html">SwingWorker</a>() {
<a name="104" href="#104">104</a>         <strong class="jxr_keyword">final</strong> Runnable doFinished = <strong class="jxr_keyword">new</strong> Runnable() {
<a name="105" href="#105">105</a>            <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> run() { finished(); }
<a name="106" href="#106">106</a>         };
<a name="107" href="#107">107</a> 
<a name="108" href="#108">108</a>         Runnable doConstruct = <strong class="jxr_keyword">new</strong> Runnable() {
<a name="109" href="#109">109</a>             <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> run() {
<a name="110" href="#110">110</a>                 <strong class="jxr_keyword">try</strong> {
<a name="111" href="#111">111</a>                     setValue(construct());
<a name="112" href="#112">112</a>                 }
<a name="113" href="#113">113</a>                 <strong class="jxr_keyword">finally</strong> {
<a name="114" href="#114">114</a>                     threadVar.clear();
<a name="115" href="#115">115</a>                 }
<a name="116" href="#116">116</a> 
<a name="117" href="#117">117</a>                 SwingUtilities.invokeLater(doFinished);
<a name="118" href="#118">118</a>             }
<a name="119" href="#119">119</a>         };
<a name="120" href="#120">120</a> 
<a name="121" href="#121">121</a>         Thread t = <strong class="jxr_keyword">new</strong> Thread(doConstruct);
<a name="122" href="#122">122</a>         threadVar = <strong class="jxr_keyword">new</strong> <a href="../../../org/graphnav/swing/SwingWorker.html">ThreadVar</a>(t);
<a name="123" href="#123">123</a>     }
<a name="124" href="#124">124</a> 
<a name="125" href="#125">125</a>     <em class="jxr_javadoccomment">/**</em>
<a name="126" href="#126">126</a> <em class="jxr_javadoccomment">     * Start the worker thread.</em>
<a name="127" href="#127">127</a> <em class="jxr_javadoccomment">     */</em>
<a name="128" href="#128">128</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> start() {
<a name="129" href="#129">129</a>         Thread t = threadVar.get();
<a name="130" href="#130">130</a>         <strong class="jxr_keyword">if</strong> (t != <strong class="jxr_keyword">null</strong>) {
<a name="131" href="#131">131</a>             t.start();
<a name="132" href="#132">132</a>         }
<a name="133" href="#133">133</a>     }
<a name="134" href="#134">134</a> }
<a name="135" href="#135">135</a> 
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